Hydrangeaceae is a family of flowering plants in the order Cornales, with a wide distribution in Asia and North America, and locally in southeastern Europe.[3]
Description
The genera are characterised by leaves in opposite pairs (rarely whorled or alternate), and regular, bisexual flowers with four (rarely 5–12) petals. The fruit is a capsule or berry containing several seeds, the seeds with a fleshy endosperm.[4]
The family Hydrangeaceae has two subfamilies, namely Jamesioideae and Hydrangeoideae. The subfamily Jamesioideae comprises the genera Jamesia and Fendlera.[6][7] They are the sister group to the remaining Hydrangeaceae.[7][8] The subfamily Hydrangeoideae has two tribes:[9][7][8] Hydrangeae consists of Hydrangea s.l.,[9] and Philadelpheae consists of Philadelphus, Carpenteria, Deutzia, Kirengeshoma, Whipplea, and Fendlerella.[7][8]Carpenteria is the sister group to Philadelphus. Deutzia is the sister group to Kirengeshoma, and Fendlerella is the sister group to Whipplea.[8][6][7] However the relationships among those three clades within the tribe Philadelphae are a bit unclear.[8] The following cladogram summarizes results from different studies, and for each node it is noted which studies support the sister group positions of the following branches: